In order to ensure a good sealed seating of the piston in the closed position, in the manufacture of the piston and the valve seat it is often necessary to adhere to very close tolerances. However, adherence to these tolerances considerably increases the manufacturing costs.
A valve of the general class to which the invention relates is disclosed in DE-A-30 15 487, but this has an additional sealing element which comes into operation when the plate-shaped sealing element breaks. Also, with this known valve seat it is still necessary to adhere to relatively close tolerances in order to ensure a good sealed seating.
The object of the invention, therefore, is to provide an improved valve construction in which the manufacturing costs are reduced.